Solar water purifier a project that can help you in your projects

1. Presented by
Rohit sen (me)
Solar Water Purification
System

2. Introduction: there is almost no water left on earth that is safe to
drink
without purification after 20-25 years today. This is a seemingly bold
statement, but it is unfortunately true. Only 1% of Earth's water is in a
fresh, liquid state, and nearly all of this is polluted by both diseases and
toxic chemicals. For this reason, purification of water supplies is
extremely important. Keeping these things in mind, we have devised a
model which will convert the dirty/saline water into pure/potable water
using the renewable source of energy (i.e. solar energy). The basic
modes of the heat transfer involved are radiation, convection and
conduction. The results are obtained by evaporation of the dirty/saline
water and fetching it out as pure/drinkable water.
The sun radiates the energy uniformly in all direction in the form of
electromagnetic waves. When absorbed by body, it increases its
temperature. It is a clean, inexhaustible, abundantly and universally
available renewable energy.
Solar energy has the greatest potential of all the sources of renewable
energy and if only a small amount of this form of energy could be
used, it will be one of the most important supplies of energy,
especially when other sources in the country have depleted

3. IDEA
solar water distillation using solar still it is not a new process, but it has not
received the attention that it deserves. Perhaps this is because it is such a
low-tech and flexible solution to water problems. Nearly anyone is capable of
building a still and providing themselves with completely pure water from very
questionable sources. Solar power where sun hits atmosphere is 1017
watts and the total demand is 1013 watts. Therefore, the sun gives us
1000 times more power than we need. If we can use 5% of this energy, it
will be 50 times what the world will require. The energy radiated by the
sun on a bright sunny day is 4 to 7 KWh per m2.
Water to be cleaned is poured into the still to partially fill the basin. The glass
cover allows the solar radiation to pass into the still, which is mostly
absorbed by the blackened base. This interior surface uses a blackened
material to improve absorption of the sunrays. The water begins to heat up
and the moisture content of the air trapped between the water surface and
the glass cover increases. The heated water vapor evaporates from the
basin and condenses on the inside of the glass cover. In this process, the
salts and microbes that were in the original water are left behind. Condensed
water trickles down the inclined glass cover to an interior collection trough
and out to a storage bottle.

4. SOLUTION
Water to be cleaned is first poured into screening and grit
chamber.
Screening is the first process used at wastewater treatment
plants (WWTP) and helps filter out objects (e.g., solid waste)
which may damage and/or clog downstream equipment. A
combination of both coarse and fine screens are utilized by
modern treatment facilities to perform such process.
Grit removal, on the other hand, involves the removal of
sand, gravel or other heavy solid materials, usually those that
have higher specific gravity than the organic biodegradable
solids in the wastewater.
Grit chamber is the second unit operation used in primary
treatment of wastewater and it is intended to remove
suspended in organic

5. From screening and grit chamber water is poured into roof-type solar
water distillation(RSWD) Water vapour condenses in the atmosphere
and returns to earth as rain water. Solar distillation represents one of the
oldest techniques and is useful for the production of fresh water from
sewage water in many parts of the world. Among the many factors
considered in the design and fabrication of a solar water distillation
system are cost implication and efficiency. As a supporting technique for
water purification, various types of solar stills have been developed and
are being applied worldwide. Generally, solar still systems have the
advantage of low operating and maintenance costs and the shortcoming
of low thermal efficiencies.
In this research work, we designed a roof-type solar water
distillation (RSWD) kit to replicate the natural process of
evaporation and condensation. In the RSWD system, a wooden
rectangular box covered with black polyethylene absorber surface
was the water tank. A glass roof was designed to rest onto the water
tank. Beneath the glass roof was a gutter or condensate channel for
driving out distilled water. The heating and evaporation took place
on the absorber surface, while condensing process to ok place on
the glass roof

6. Aeration brings water and air in close contact in order to remove dissolved gases
(such as carbon dioxide) and oxidizes dissolved metals such as iron, hydrogen
sulfide, and volatile organic chemicals (VOCs). Aeration is often the first major
process at the treatment plant. During aeration, constituents are removed or
modified before they can interfere with the treatment processes.
Aeration brings water and air in close contact by exposing drops or thin sheets of
water to the air or by introducing small bubbles of air (the smaller the bubble, the
better) and letting them rise through the water. The scrubbing process caused by
the turbulence of aeration physically removes dissolved gases from solution and
allows them to escape into the surrounding air.
Aeration also helps remove dissolved metals through oxidation, the chemical
combination of oxygen from the air with certain undesirable metals in the water.
Once oxidized, these chemicals fall out of solution and become particles in the
water and can be removed by filtration or flotation.
The efficiency of aeration depends on the amount of surface contact between air
and water, which is controlled primarily by the size of the water drop or air bubble.
Oxygen is added to water through aeration and can increase the palpability of
water by removing the flat taste. The amount of oxygen the water can hold
depends primarily on the temperature of the water. (The colder the water, the
more oxygen the water can hold).
Water that contains excessive amounts of oxygen can become very corrosive.
Excessive oxygen can also cause problems in the treatment plant i.e. air binding
AERATION CHAMBER

7. CHEMICALS REMOVED OR OXIDIZED BY AERATION
Constituents commonly affected by aeration are:
Volatile organic chemicals, such as benzene (found in gasoline), or
trichloroethylene, dichloroethylene, and perchloroethylene (used in dry-
cleaning or industrial processes)
Ammonia
Chlorine
Carbon dioxide
Hydrogen sulfide
Methane
Iron and Manganese

8. EXPERIMENTAL SET-UP
A single slope single basin solar still is fabricated from a Galvanized Iron sheet as basin and as well as
heat reservoir. The outer case is made of ply wood and inner case is made of Galvanized Iron and the
gap between these two is filled by insulating material. The rectangular box is made taper and it is
sealed by means of a non-reflective transparent window glass. Lower basin with energy storage
material and upper basin with water has been filled.
Thermocouples are fixed with an adhesive at suitable required positions by drilling holes in to GI and
wooden frame and other end is connected to a temperature indicator. The solar radiation incident on
the cover is absorbed and transfers the same to water in the basin and it gets heated up. The water is
evaporated due to the gradual increase in temperature of water and it is condensed and collected at
the lower end of the cover. A rectangular channel with a small pipe is placed to collect and to send the
distillate outside the still.
The solar still is kept at a place where there was no shade throughout the day and the readings are
noted down in such a way that the equilibrium of the system is not disturbed. Also, the still is kept
closed to prevent any type of leakages and losses.

9. Water tank
Absorber surface
Water tap
water
Gutter
Figure-1
The rectangular water tank on top of RSWD
stand
Water tap
Glass
Water
Figure-2
The glass roof on top of the rectangular water

10. performance of solar concentrated distiller with latent heat storage
material was compared with solar concentrated distiller with tray basin.
Valves are used to control the flow of saline water to the Integrated
Performance Analysis of Latent Heat Storage and basin of the
concentrator. Basin of length 0.9m and diameter 0.15m is provided for
evaporating the saline water. It is fabricated of 2 mm thick GI sheet and
coated with black paint to increase the absorption of heat. Parabolic
concentrator of length 1m and width 0.5m, depth 0.125m is used to
concentrate solar thermal energy to the basin made out glass mirror.
These dimensions were calculated based on which concentration of
sunlight focuses on the basin. Concentrator is tilted to various angles
manually every hour. Basin is covered with double slope glass cover for
condensing the distilled water. One of the basin is enhanced with pipes
containing paraffin wax, which acts as latent heat storage material for the
system. And another basin has segmented fins on the basin, which
improves the exposure area of the basin. Comparison of performance is
based on productivity of the distiller between 10 A.M to 5P.M. Glass cover
is inclined in 10 degree on both sides. Leather sheet was used to
prevent leakage from any gap between the glass covers and the still box
Poly Vinyl Chloride (PVC) tubes were used to discharge the distilled
water from each unit to the bottles. The inlet water was fed into the still

11. Performance of a still
The experiment is carried out for the month of June with and without (Phase
change Material) PCM from 8:00 am to 10:00 pm without PCM and 8:00 am to
12:00 am with PCM. The temperatures of the glass cover and other elements of
the still are determined by means of a Data logger (Temperature indicator). The
readings are tabulated and various heat transfer coefficients h1, h2, h3, hewg are
evaluated with the help of available formulae [3, 8, 9, 10]. The heat transfer and
energy balancing equations are solved numerically and productivity, efficiency are
calculated by using the below mentioned formulae. Also, comparisons are
illustrated graphically. Various graphs are presented with and without using Phase
change Material. Cumulative productions of fresh water are also represented and
compared.

12. Material and Methods
RSWD water basin whose interior has been covered with black
polyethylene. The 91cm x 56cm rectangular water tank is 22cm deep.
The water tap is for discharging of untreated water sample should the
need arise. The condensate channel was made of aluminium sheets,
while the wooden frame that formed the water basin also served as
thermal insulator.
Figure 2 shows the glass roof, outlets for distilled water and RSWD
stand. Two sheets of glass, about 90.8cm long, 61.2cm wide and 3mm
thick were rightly placed to form the glass roof. Each of the two edges of
the glass roof was covered with a triangular glass sheet of two equal
sides and a base of 57.8cm. A 2-in-1 chemmer fast epoxy glue was
used to hold the glass roof in place.
Solar energy warms the absorber surface and some of the water
evaporates and condenses on the glass roof. The condensate flows into
the condensate channel and is taken out through a hose pipe. The
volume of distilled water produced hourly by the RSWD kit was
measured for six consecutive days.

13. Results and discussions
Fig 4.1 it is observed that
in the month of June, the
intensity of solar radiation
is decreased. Compared
to that in summer the
earth gets cooled by slight
rainfall. So, there is
sudden decline in the
Intensity of solar radiation
as the day is cloudy.
However, at noon solar
radiation is maximum at 1-
2 pm

14. Fig 4.2 shows as the intensity of
solar radiation decreases, so
there is a simultaneous
decrease in the output. Hence
the fresh water production is
decreased due to the decline in
the intensity of solar radiation
and the production is maximum
at 3 pm.
Fig 4.3 shows a comparison is
made between glass and water
temperatures. Since solar
intensity is low, the still will not
achieve higher temperatures
compared to that in Summer. At
1-2 pm the glass and water
attain maximum temperatures.

15. Fig 4.7 shows the productivity
increases for both summer
and winter for PCM, water
then normal still. It is clear
that the still is effective with a
PCM and then more efficient
when sand is used as a HR.
For, both the seasons the still
works better with the PCM
only. 15-20 % increase in
Efficiency is observed.

16. Conclusions
1. The still continues to produce the fresh water even
after sunset by the addition of a heat reservoir
2. The distillate production is said to be increased to
36% with PCM
3. Tests proved that the water is as pure as rain water
and there are no harmful salts at all
4. It is suggested that for higher masses of PCM, the
still will be more effective